Apparatus and method for separating a stack of sheets

ABSTRACT

A plasterboard wedge has an acute edge that is sufficiently thin to be inserted between the edges of consecutive plasterboard sheets arranged in a stack. The wedge is then pressed into the stack to form a gap on both lateral sides of the wedge into which the forks of a fork-lift can be inserted. The fork-lift can then lift the desired number of plasterboard sheets off the stack onto a vehicle. A tip of one of the fork-lift forks is used to press the wedge into the stack, and is located in a horizontal groove in the blunt face to prevent relative vertical slipping.

FIELD OF THE INVENTION

This invention provides apparatus for, and a method of, improving the handling of sheets. More particularly, but not exclusively, the invention relates to apparatus and method for separating a stack of plasterboard sheets. Embodiments of the invention relate to wedges, such as plasterboard wedges.

BACKGROUND TO THE INVENTION

Sheets of plasterboard are supplied to builders merchants as large sheets of plasterboard are supplied to builders' merchants as large stacks supported by a pallet. To supply a purchaser, it is currently necessary to slide the requisite number of sheets one-by-one off the top of the stack, thereby incurring the problem of man-handling large, heavy and fragile sheets. When a plurality of such sheets are to be supplied, it is then necessary to re-stack them on the builder's vehicle. Fork-lift trolleys and fork-lift trucks are sometimes used to transfer the sheets of plasterboard between the stack and the builder's vehicle, the sheets being man-handled one-by-one from the stack onto the forks of the fork lift.

SUMMARY OF THE INVENTION

According to one aspect of this invention, a wedge comprises first and second splitting members arranged at an acute angle to one another to provide an insertion edge that is sufficiently thin to allow insertion of the wedge between consecutive sheets in a stack of sheets, and an engagement means opposite to the insertion edge to engage a pushing implement, whereby the wedge can be pushed between said consecutive sheets by said pushing implement.

A first embodiment of the invention is suitable for use in separating consecutive plasterboard sheets from a stack of plasterboard sheets. In the first embodiment, the wedge may be a plasterboard wedge.

The first and second splitting members may comprise first and second faces respectively.

The engagement means may comprise a blunt face of the wedge for engagement with the pushing implement. The engagement means may comprise a locator for engagement with the pushing implement.

The locator may be a formation to receive the pushing element. In one embodiment, the locator may be a groove formed in the blunt face.

According to another aspect of the invention, a wedge has an acute edge that is sufficiently thin to allow insertion between consecutive sheets in a stack of sheets, has a blunt face that is opposite to the acute edge and is thicker than the operative end portion of the forks of a fork-lift truck, and a width that will fit horizontally between said forks. Although the tips of the forks of a fork-lift cannot be inserted between consecutive plasterboard sheets without causing substantial damage, I have found that the acute edge of my plasterboard wedge can be inserted without causing such damage partly because of the acute angle of my wedge, and partly due to the slight elastic compressibility of the edges of the plasterboard sheets.

The blunt face preferably defines an abutment for engagement with one or other of the forks whereby the fork can be utilised to press the plasterboard wedge between the consecutive plasterboard sheets. Although this abutment may be of any convenient form, I prefer using a horizontal groove formed in the blunt face for receiving a tip of one of said forks.

My plasterboard wedge can be formed of any suitable material, for instance hardwood or a moulding of a hard thermosetting plastics material.

The angle of the acute edge is preferably between 5° and 110 but I have found that an angle of about 8° is particularly suitable.

If desired, the insertion edge may be formed of a metallic material, or may have a cover formed of a metallic material. The metallic material may extend from the insertion edge towards the engagement means.

According to another aspect of this invention, a method of separating a stack of sheets comprises inserting an edge of a wedge between consecutive sheets, and then pushing the wedge into the stack to separate the sheets to establish a gap between the consecutive sheets, said gap being sufficiently large to enable the insertion of lifting elements between said consecutive sheets.

The wedge may include an engagement formation, and the method may comprise locating a pushing implement in the engagement formation, and thereafter pushing the wedge into the stack.

The method may comprise using one of the lifting elements to push the wedge into the stack. The lifting elements may comprise forks of a fork-lift, and the method may comprise using a fork of the fork-lift to push the wedge into the stack.

The method may further comprise inserting the forks of the fork-lift into the gap on either side of the wedge, and using the fork-lift to lift the separated sheets from the stack.

According to another aspect of my invention, a method of separating a stack of plasterboard sheets comprises inserting the acute edge of a plasterboard wedge between consecutive plasterboard sheets, and then pressing the wedge into the stack to separate the sheets to establish a gap sufficiently large to enable the insertion of the forks of a fork-lift. The method preferably further comprises using a fork of the fork-lift to press the plasterboard wedge into the stack.

The method preferably further comprises inserting the forks of the fork-lift into the gap on either side of the plasterboard wedge, and using the fork-lift to move the separated sheets from the stack.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of example only, with reference to the accompanying drawings, in which:—

FIG. 1 is a side elevation of a plasterboard wedge;

FIG. 2 is a plan view of the wedge shown in FIG. 1;

FIG. 3 is an end elevation taken in the direction of arrow 3 in FIG. 1;

FIG. 4 is an end elevation taken in the direction of arrow 4 in FIG. 1;

FIG. 5 is a diagrammatic side view of the insertion of a wedge into a stack of sheets;

FIG. 6 is a diagrammatic side view of a wedge having been inserted into a stack of sheets; and

FIG. 7 is a diagrammatic sectional view of forks of a fork-lift being inserted between consecutive sheets separated by a wedge.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

In the drawings, a wedge, in the form of a plasterboard wedge, is indicated generally by arrow W and is used to separate consecutive sheets 18, 20 of plasterboard in a stack 22 of plasterboard sheets (see FIGS. 5 to 7).

The plasterboard wedge W has a first face in the form of an upper surface 10, a second face in the form of a lower surface 11, and opposed side faces 12 and 13. The upper and lower surfaces 10, 12 are arranged at an acute angle to each other to provide an insertion edge 14. At the edges of the upper and lower faces 10, 12 opposite the insertion edge a blunt face 15 is provided.

The upper and lower surfaces 10 and 11 are mutually inclined at an acute angle α which is preferably about 8° where the plasterboard wedge is made from hardwood, but could be in the range 5° to 11°, the angle being dependent on the coefficient μ of surface friction between the material forming the plasterboard wedge and the surface of the plasterboard.

Where the plasterboard wedge W is made from hardwood, the grain extends between the acute edge 14 and the blunt face 15.

Desirably, the plasterboard wedge W is moulded from a hard thermosetting plastics material such moulding facilitating production and the use of a plastics material enabling the working surfaces 10 and 11 to be formed true and smooth.

The length of the plasterboard wedge W is determined by the angle α and the objective that the surfaces 10 and 11 adjacent the blunt face 15 will open a gap between consecutive plasterboard sheets that is sufficiently large to enable the insertion of the forks of a fork-lift.

The width of the plasterboard wedge W is chosen to be slightly less than the separation of the forks of the fork-lift so that the forks can be simply moved into the gaps generated along both edges of the plasterboard wedge W.

Referring to FIGS. 5 to 7, which show the plasterboard wedge W in use. The plasterboard wedge W has its insertion edge 14 manually inserted between the chosen consecutive plasterboard sheets, and is then pressed inwards to form a gap needed by one of the forks 24 of a fork-lift 26, shown diagrammatically in FIG. 5. This pressing is achieved by using the tip of the fork 24 to engage the blunt face 15, and then moving the fork-lift towards the stack, in the direction indicated by the arrow A.

To counter any possible slippage between the tip of the fork and the blunt face 15, a horizontal groove 16 is provided to receive the tip of the fork thereby preventing any relative vertical movement. Instead of using the horizontal groove 16, other forms of abutment could be used, for instance a socket for receiving the fork tip.

When the plasterboard wedge W has been inserted a sufficient distance, for example as shown in FIG. 6, a gap 28 (see FIG. 7) is created between the consecutive plasterboard sheets 18, 20. The forks 24 of the fork-lift 26 are then inserted into the gap 28 on either side of the plasterboard wedge W. The forks 24 are shown in a cross-sectional view in FIG. 7. The plasterboard sheet 18, and those thereabove, can then be lifted by the fork-lift 26 from the remaining plasterboard sheets in the stack 22. 

1. A wedge comprising first and second splitting members arranged at an acute angle to one another to provide an insertion edge that is sufficiently thin to allow insertion of the wedge between consecutive sheets in a stack of sheets, and an engagement formation opposite to the insertion edge to engage a pushing implement, whereby the wedge can be pushed between said consecutive sheets by said pushing implement.
 2. A wedge according to claim 1, wherein the engagement formation comprises a blunt face of the wedge for engagement with the pushing implement.
 3. A wedge according to claim 2, wherein the engagement formation comprises a locator for engagement with the pushing implement.
 4. A wedge according to claim 3, wherein the locator is a formation to receive the pushing implement.
 5. A wedge according to claim 4, wherein the locator is a groove formed in the blunt face for receiving the pushing implement.
 5. A wedge according to claim 1, formed as a moulding of a hard thermosetting plastics material.
 6. A wedge according to claim 1, wherein the acute angle between the first and second faces is between 5° and 11°.
 7. A wedge according to claim 6, wherein the acute angle between the first and second faces is about 8°.
 8. A wedge according to claim 1 wherein the insertion edge is selected from the group of consisting of (a) being formed of a metallic material and (b) being covered by a metallic material.
 9. A wedge according to claim 8, wherein the metallic material extends from the insertion edge towards the engagement means.
 10. A wedge according to claim 9, wherein the metallic material extends from the insertion edge part way to the engagement means.
 11. A method of separating a stack of sheets comprising inserting an edge of a wedge between consecutive sheets, and then pushing the wedge into the stack to separate the sheets to establish a gap between the consecutive sheets, said gap being sufficiently large to enable the insertion of lifting elements between said consecutive sheets.
 12. A method according to claim 11, wherein the wedge includes an engagement formation, and the method comprises locating a pushing implement in the engagement formation, and thereafter pushing the wedge into the stack.
 13. A method according to claim 12, comprising using one of the lifting elements to push the wedge into the stack.
 14. A method according to claim 13, wherein the lifting elements comprise forks of a fork-lift, and the method comprises using a fork of the fork-lift to push the wedge into the stack.
 15. A method according to claim 14, further comprising inserting the forks of the fork-lift into the gap on either side of the wedge, and using the fork-lift to lift the separated sheets from the stack. 